#include <iostream>
#include "head.h"

using namespace std;

int main()
{
    int a = 10;
    int b = 20;
    cout << "a + b = " << add(a, b)<< endl; 
    cout << "a - b = " << sub(a, b) << endl; 
    cout << "a * b = " << mul(a, b) << endl; 
    // cout << "a / b = " << div(a, b) << endl; 
    return 0;
}